JP2015170492A - tact switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tact switch in which an expandable part of a protecting member is configured to be sufficiently deformed expandably according to elastic deformation of a plate spring even if the plate spring decreases gradually in size so that a length of the expandable part is reduced, so as allow a switch function of the plate spring to be surely exerted.SOLUTION: A tact switch includes: a dome-like plate spring 12 which is provided on a print circuit board 11 and arranged so that an outer peripheral edge part thereof contact fixed contact points 11a and 11b at both sides and an apex part 12a thereof is positioned on fixed contact points 11a and 11b at a center; a spacer 13 that is provided on the print circuit board 11 and provides a space part for storing the plate spring 12; and a protecting member 14 that is tightly adhered to the upper face of the spacer 13 and the apex part of the plate spring 12 and holds the plate spring in the space part of the spacer 13. In a part of the protecting member 14 to be tightly adhered to the upper face of the spacer 13 with an adhesive is formed a non-adhered part to which the adhesive is not applied, and a plurality of non-adhered parts are formed along an edge part of the plate spring 12.

Description

  The present invention relates to a tact switch, and more particularly to a tact switch used for a switch device of a portable terminal or an electronic device.

  In general, the tact switch is provided on the printed circuit board 1 having a plurality of fixed contacts 1a and 1b formed on the upper surface as shown in FIG. 1 and the outer peripheral edge is fixed on both sides. The vertex 2a is in contact with the contact 1b, and provides a dome-shaped leaf spring (metal dome) 2 disposed so as to be positioned on the center fixed contact 1a, and a space portion 3a in which the leaf spring 2 is received. The spacer 3 is composed of a protective sheet 4 that is fixed to the upper surface of the spacer 3 and the apex 2a of the leaf spring 2 with an adhesive 4a to hold the leaf spring 2 in the space 3a of the spacer 3. Yes.

  Therefore, when a pressing force is applied to the apex portion 2a of the leaf spring 2, the apex portion 2a of the leaf spring 2 is elastically deformed downward as shown in FIG. 2A, and the plate contacts the fixed contact 1a at the center of the printed circuit board 1. The apex 2a of the spring 2 comes into contact. On the other hand, when the pressing force is released, the apex portion 2a of the leaf spring 2 returns to the original position by the elastic restoring force, and the apex portion 2a of the leaf spring 2 is separated from the center fixed contact. As a result, it is possible to perform a switch function for portable terminals and electronic devices.

  As shown in FIG. 2A, the tact switch operating as described above is fixed to the apex 2a of the leaf spring 2 and the spacer 3 when the apex 2a of the leaf spring 2 is elastically deformed downward. The protective sheet 4 must also be deformed so as to move downward together. Therefore, the protective sheet 4 is made of a material that is elastic to some extent to an external force, for example, a thin film of a synthetic resin material.

  However, the size of the leaf spring 2 of the tact switch becomes smaller and smaller as mobile terminals and electronic devices become smaller. Accordingly, as shown in FIG. 1, the length (between the adhesive portion a of the spacer 3 and the adhesive portion b of the leaf spring 2 at the adhesive portion a of the spacer 3 excluding the adhesive portions a and b in the protective sheet 4 ( The stretchable part L is also gradually shortened. When the length of the expansion / contraction part L is insufficient during the pressing operation of the leaf spring 2, the amount of deformation in the expansion / contraction part L is small as shown in FIG. There is a problem in that the fixed contact 1a cannot be contacted and the switch function is not performed.

  Accordingly, the present invention, which has been made to solve the conventional problems as described above, provides the elasticity of the leaf spring even when the length of the stretchable portion of the protective sheet is shortened by gradually reducing the size of the leaf spring. The object is to provide a tact switch that is configured so that the expansion and contraction of the expansion and contraction part is sufficiently performed according to the deformation and that can reliably exhibit the switch function of the leaf spring.

  In order to achieve the above-described object, a tact switch according to an aspect of the present invention includes a printed circuit board having a plurality of fixed contacts formed on an upper surface thereof; the printed circuit board is provided on the printed circuit board; A dome-shaped leaf spring disposed so as to be in contact with the stationary contact and having the apex portion positioned on the central stationary contact; a spacer provided on the printed circuit board and providing a space for accommodating the leaf spring A protective sheet that is fixed to the upper surface of the spacer and the apex of the leaf spring with an adhesive to hold the leaf spring in the space of the spacer, and the protective sheet provided on the upper surface of the spacer includes: A non-adhering part to which an adhesive is not applied is provided in part, and the non-adhering part is formed at a plurality of locations along the edge of the leaf spring.

  A tact switch according to another aspect of the present invention includes a printed circuit board having a plurality of fixed contacts formed on an upper surface thereof; the printed circuit board is provided on the printed circuit board, and an outer peripheral edge thereof is in contact with the fixed contacts on both sides. A dome-shaped leaf spring disposed so as to be positioned on a central fixed contact; a spacer provided on the printed circuit board and providing a space for accommodating the leaf spring; and an upper surface of the spacer An intermediate sheet fixed to the upper surface of the intermediate sheet and an apex of the leaf spring, and a protective sheet for holding the leaf spring in the space of the spacer. The protective sheet provided on the upper surface of the plate is provided with a non-adhering portion where no adhesive is applied to a part thereof, and the non-adhering portion is formed at a plurality of locations along the edge of the leaf spring.

  At this time, it is preferable that the non-adhering portion is formed on one or both of the longitudinal and widthwise edges of the leaf spring.

  Moreover, it is preferable that the said protective sheet is provided with the wrinkle part provided so that it could be expanded-contracted smoothly according to the vertex part of the said leaf | plate spring being pressed and elastically deformed.

  At this time, the wrinkle portion is a plurality of linear grooves formed in the protective sheet, and the linear grooves are formed in a lattice shape on the protective sheet, or the leaf spring is formed on the protective sheet. It is preferable to form a groove having the same pattern as the pattern along the edge portion, and to form a plurality of the grooves at regular intervals or by embossing the protective sheet.

  According to the present invention having such a characteristic configuration, the non-adhering portion where the adhesive is not applied to the protective sheet or the intermediate sheet fixed to the upper surface of the spacer with the adhesive is provided at a plurality of locations along the edge of the leaf spring. Since it is formed, when the apex of the leaf spring is pressed and elastically deformed, the amount of deformation of the expansion / contraction portion of the protective sheet deformed accordingly can be further increased, and thereby the size of the leaf spring Even when the length is gradually reduced and the length of the stretchable portion of the protective sheet is short, the switch function of the leaf spring can be reliably exhibited.

  Further, according to the present invention, since the wrinkle portion is formed in the expansion / contraction portion of the protective sheet, the deformation amount of the expansion / contraction portion of the protection sheet is further increased in accordance with the elastic deformation of the leaf spring, thereby, It is a useful invention that can exhibit the above even more reliably.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)

  3 and 4 are a plan view and a cross-sectional view showing the tact switch according to the first embodiment of the present invention. As shown in this drawing, the tact switch according to the first embodiment of the present invention includes a printed circuit board 11 having a plurality of fixed contacts 11a and 11b formed on the upper surface, and a dome provided on the printed circuit board 11. Shaped leaf spring 12.

  The leaf spring 12 is arranged so that the outer peripheral edge thereof is in contact with the fixed contacts 11b on both sides of the printed circuit board 11, and the apex 12a is located on the central fixed contact 11a. When the apex portion 12a is pressed and elastically deformed downward or the pressing force is released, the leaf spring 12 performs a switching function while contacting or separating from the central fixed contact 11a.

  A spacer 13 is provided on the printed circuit board 11. The spacer 13 is formed with a space portion 13 a for accommodating the leaf spring 12, and the leaf spring 12 is formed by a protective sheet 14 fixed with an adhesive 14 a across the upper surface of the spacer 13 and the top surface 12 a of the leaf spring 12. Is held in the space of the spacer 13.

  In the present invention, a non-adhering portion 14b to which the adhesive 14a is not applied is formed on a part of the protective sheet 14 provided on the upper surface of the spacer 13. At this time, it is preferable that the non-adhering portion 14 b is formed at a plurality of locations along the edge of the leaf spring 12.

  For example, the non-attachment portion 14b is preferably formed on both the longitudinal and width edges of the leaf spring 12, as shown in FIG. 3, and the non-attachment portion 14b is not attached as shown in FIGS. 6A and 6B. The portion 14b may be formed on one of the longitudinal direction and the widthwise edge of the leaf spring 12.

  As shown in FIGS. 4 and 5, the tact switch according to the first embodiment of the present invention configured as described above is configured to press the apex portion 12a of the leaf spring 12 or release the pressing force. While 12 is elastically deformed downward or returns upward, the apex 12a contacts or separates from the central fixed contact 11a to perform a switching function. In accordance with such elastic deformation of the apex portion 12a, deformation also occurs between the stretchable portion L of the protective sheet 14, that is, between the adhesion portion a with the spacer 13 and the adhesion portion b with the leaf spring 12.

At this time, as shown in FIG. 3, the protective sheet 14 includes a non-adhering portion 14 b that does not apply the adhesive 14 a between the spacer 13 and the protective sheet 14. Therefore, as shown in FIGS. 4 and 5, the deformation amount in the expansion / contraction part L can be further increased by the non-attachment part 14 b of the protective sheet 14 according to the elastic deformation of the leaf spring 12. As a result, a malfunction has occurred in the operation of the switch due to a poor contact between the apex portion 12a and the central fixed contact 11a, which has occurred in the past because the expansion / contraction portion L is not sufficiently deformed. Problems can be prevented.
(Second Embodiment)

  FIG. 7 is a cross-sectional view of a tact switch according to a second embodiment of the present invention. Compared to the first embodiment described above, the height of the spacer 13 is divided, and an intermediate sheet 15 is further provided between the spacer 13 and the protective sheet 14, and other configurations are the same as in the first embodiment. It is the same. Accordingly, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description of the structure and operation is omitted.

  The intermediate sheet 15 has an upper surface fixed to the protective sheet 14 with an adhesive 14a and a bottom surface fixed to the spacer 13 with an adhesive 15a. At this time, in the process of attaching the upper surface of the intermediate sheet 15 to the protective sheet 14, the adhesive 14a is applied to the entire upper surface of the intermediate sheet 15 as shown in FIG. 9A, and the bottom surface of the intermediate sheet 15 is shown in FIG. 9B. As described above, the adhesive 15 a is applied to the upper surface of the spacer 13, but non-adhering portions 15 b that do not apply the adhesive 15 a are partially formed along the edge of the leaf spring 12 at a plurality of locations.

  For example, as shown in FIG. 9B, the non-adhering portion 15b is preferably formed on both the longitudinal and widthwise edges of the leaf spring 12, as shown in FIGS. 6A and 6B of the first embodiment. Thus, you may form in either one among the edge part of the longitudinal direction of the leaf | plate spring 12, and the width direction.

  According to the tact switch according to the second embodiment of the present invention configured as described above, as shown in FIGS. 7 and 8, the apex portion 12a of the leaf spring 12 is pressed and elastically deformed downward, or When the pressing force is released to return upward, the apex portion 12a performs a switch function while contacting or separating from the central fixed contact 11a. In accordance with such elastic deformation of the apex portion 12 a, deformation occurs between the stretchable portion L of the protective sheet 14, that is, the adhesion portion a with the spacer 13 and the adhesion portion b with the leaf spring 12.

  At this time, also in the second embodiment, as in the first embodiment, the intermediate sheet 15 fixed to the upper surface of the spacer 13 includes a non-adhering portion 15b to which the adhesive 15a is not applied, as shown in FIG. 9B. Yes. Therefore, as shown in FIGS. 7 and 8, the deformation amount of the stretchable portion L of the protective sheet 14 can be further increased in accordance with the elastic deformation of the leaf spring 12. As a result, a malfunction has occurred in the operation of the switch due to a poor contact between the apex portion 12a and the central fixed contact 11a, which has occurred in the past because the expansion / contraction portion L is not sufficiently deformed. Problems can be prevented.

Further, in the second embodiment, the height of the non-adhesive portion 15b is positioned lower than the height of the non-adhesive portion 14b in the first embodiment by the thickness of the intermediate sheet 15, so that protection is provided according to the elastic deformation of the leaf spring 12. A sufficient amount of deformation in the stretchable portion L of the sheet 14 can be ensured.
(Third embodiment)

  FIG. 10 is a plan view of a tact switch showing a third embodiment of the present invention. Compared to the configuration of the first embodiment described above, it has a configuration in which the wrinkle portion 16 is formed in the expansion / contraction portion L of the protective sheet 14, and is otherwise the same as the configuration of the first embodiment. Accordingly, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description of the structure and operation is omitted.

  The wrinkle portion 16 is configured such that when the apex portion 12a of the leaf spring 12 is elastically deformed by pressing, the stretchable portion L of the protective sheet 14 is smoothly stretched and deformed accordingly.

  The wrinkle portion 16 is a portion excluding the adhesion portion a with the upper surface of the spacer 13 and the adhesion portion b with the upper surface of the apex portion 12a of the leaf spring 12, that is, the adhesion portion a with the spacer 13 and the adhesion portion b with the leaf spring 12. It is preferable to form in the expansion-contraction part L between.

  The wrinkle portion 16 can be easily configured, for example, by forming a plurality of linear grooves in the protective sheet 14 and forming the linear grooves in a lattice shape as shown in FIG. At this time, the groove is preferably formed on both the upper surface and the lower surface of the protective sheet 14 as shown in FIG. 11A. Although not shown in the drawing, only one of the upper surface and the lower surface of the protective sheet 14 is formed. You may form a groove | channel in this. Alternatively, the groove may be formed by removing a part of the surface of the protective sheet 14 through a predetermined process, or the protective sheet 14 may be formed by press molding.

  Further, as a modification of the wrinkle portion 16, as shown in FIG. 12A, a groove having the same pattern as the pattern along the edge portion of the leaf spring 12 may be formed in the protective sheet 14. In this case, it can be easily configured by forming a plurality of grooves at regular intervals, or by forming circular irregularities on the protective sheet 14 by embossing as shown in FIG. 12B.

  According to the present invention configured as described above, as shown in FIGS. 11A and 11B, the vertex 12a of the leaf spring 12 is pressed and elastically deformed downward, or the pressing force is released to return upward. By doing so, the apex portion 12a performs a switching function while being in contact with or separated from the central fixed contact 11a. The elastic part L of the protective sheet 14 is also deformed together with such elastic deformation of the apex part 12a.

At this time, in the third embodiment, in addition to the configuration of the first embodiment, the wrinkle portion 16 formed in the stretchable portion L of the protective sheet 14 is configured to be more easily stretched and deformed. Even if the size of the leaf spring 12 is reduced and the length of the wrinkle-shaped expansion / contraction portion L is shortened, the expansion / contraction portion L can be easily expanded and contracted to cope with the elastic deformation of the apex portion 12a. Therefore, conventionally, the malfunction of the switch has also occurred due to the poor contact between the apex portion 12a and the central fixed contact 11a, which occurs because the expansion / contraction portion L is not sufficiently deformed. The problem can be prevented.
(Fourth embodiment)

  13A and 13B are sectional views of a tact switch showing a fourth embodiment of the present invention. Compared to the configuration of the second embodiment described above, it has a configuration in which the wrinkle portion 16 is formed in the stretchable portion L of the protective sheet 14, and is otherwise the same as the configuration of the second embodiment. Accordingly, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description of the structure and operation is omitted.

  According to such a configuration, as in the third embodiment described above, in addition to the configuration of the second embodiment, expansion and contraction deformation is further facilitated by the wrinkle portion 16 formed in the expansion / contraction portion L of the protective sheet 14. Since the size of the leaf spring 12 is reduced and the length of the wrinkle-shaped expansion / contraction part L is shortened, the expansion / contraction part L can be easily expanded and contracted to cope with the elastic deformation of the apex part 12a. It becomes like this. As a result, a malfunction has occurred in the operation of the switch due to a poor contact between the apex portion 12a and the central fixed contact 11a, which has occurred in the past because the expansion / contraction portion L is not sufficiently deformed. Problems can be prevented.

  As described above, according to the present invention, the non-adhering portion where the adhesive is not applied to the protective sheet or the intermediate sheet fixed to the upper surface of the spacer with the adhesive is formed at a plurality of locations along the edge of the leaf spring. Therefore, when the top portion of the leaf spring is pressed and elastically deformed, the amount of deformation of the expansion / contraction portion of the protective sheet deformed accordingly can be further increased, and thereby the size of the leaf spring is gradually reduced. Thus, even when the length of the expansion / contraction part of the protective sheet is short, the switch function of the leaf spring can be surely exhibited. Therefore, it can be said that the industrial applicability of the present invention is extremely high.

  On the other hand, while the invention has been described in terms of several preferred embodiments within the present specification, many variations and modifications will occur to those skilled in the art without departing from the scope and spirit of the invention as disclosed in the appended claims. It should be understood that can be made.

It is sectional drawing which showed the conventional tact switch. 2A and 2B are cross-sectional views showing the operating state of a conventional tact switch. 2A and 2B are cross-sectional views showing the operating state of a conventional tact switch. It is a top view of the tact switch concerning a 1st embodiment of the present invention. It is sectional drawing about the AA line of FIG. It is sectional drawing which showed the operation state of the tact switch which concerns on 1st Embodiment of this invention. 6A and 6B are plan views of a modification showing a non-adhering portion of the protective sheet in the first embodiment of the present invention. 6A and 6B are plan views of a modification showing a non-adhering portion of the protective sheet in the first embodiment of the present invention. It is sectional drawing of the tact switch which concerns on 2nd Embodiment of this invention. It is sectional drawing which showed the operation state of the tact switch which concerns on 2nd Embodiment of this invention. 9A and 9B are a plan view and a bottom view showing an attached state of an intermediate sheet provided between the spacer and the protective sheet in the second embodiment of the present invention. 9A and 9B are a plan view and a bottom view showing an attached state of an intermediate sheet provided between the spacer and the protective sheet in the second embodiment of the present invention. It is the top view which showed the tact switch which concerns on 3rd Embodiment of this invention. 11A and 11B are cross-sectional views taken along the line BB in FIG. 10 and are cross-sectional views showing the operating state of the tact switch. 11A and 11B are cross-sectional views taken along the line BB in FIG. 10 and are cross-sectional views showing the operating state of the tact switch. 12A and 12B are plan views showing another modification of the wrinkle portion in the third embodiment. 12A and 12B are plan views showing another modification of the wrinkle portion in the third embodiment. 13A and 13B are cross-sectional views showing the operating state of the tact switch according to the fourth embodiment of the present invention. 13A and 13B are cross-sectional views showing the operating state of the tact switch according to the fourth embodiment of the present invention.

DESCRIPTION OF SYMBOLS 11 Printed circuit board 11a, 11b Fixed contact 12 Leaf spring 13 Spacer 14 Protection sheet 14a, 15a Adhesive 14b, 15b Non-adhesion part 16 Wrinkle part L Elastic part

Claims (4)

A printed circuit board having a plurality of fixed contacts formed thereon;
A dome-shaped leaf spring provided on the printed circuit board, the outer peripheral edge portion being in contact with the fixed contacts on both sides, and the apex portion being located on the central fixed contact;
A spacer provided on the printed circuit board and providing a space for accommodating the leaf spring;
A protective sheet that is secured to the top surface of the spacer and the apex of the leaf spring with an adhesive to hold the leaf spring in the space of the spacer;
The protective sheet provided on the upper surface of the spacer includes a non-adhering portion that does not apply an adhesive to a part of the protective sheet, and the non-adhering portion is formed at a plurality of locations along an edge of the leaf spring. Tact switch to be used. A printed circuit board having a plurality of fixed contacts formed thereon;
A dome-shaped leaf spring provided on the printed circuit board, the outer peripheral edge portion being in contact with the fixed contacts on both sides, and the apex portion being located on the central fixed contact;
A spacer provided on the printed circuit board and providing a space for accommodating the leaf spring;
An intermediate sheet secured to the upper surface of the spacer with an adhesive;
A protective sheet that is secured to the upper surface of the intermediate sheet and the apex of the leaf spring with an adhesive to hold the leaf spring in the space of the spacer;
The protective sheet provided on the upper surface of the spacer includes a non-adhering portion that does not apply an adhesive to a part of the protective sheet, and the non-adhering portion is formed at a plurality of locations along an edge of the leaf spring. Tact switch to be used.   2. The tact switch according to claim 1, wherein the non-attachment portion is formed on one or both of a longitudinal direction and a width direction edge of the leaf spring.   2. The tact switch according to claim 1, wherein the protective sheet includes a wrinkle portion that is provided so as to smoothly expand and contract in response to the elastic deformation of the top portion of the leaf spring that is pressed. 3. .